@Aaronut: I totally knew the positive effects and reasons of adding salt to the water. But I was wondering WHEN is the best timing to put it. Different question.
–
Nicolas RaoulJan 27 '13 at 2:59

Well, I don't think the answers here have been any more illuminating, really; the top-upvoted one is just repeating what the other question says. Convention is generally to add salt before pasta, as that is what the package directions actually always say ("add to [syz amount] of rapidly boiling salted water"), clearly that is the "best practice", so are you asking what would change if you added salt later?
–
Aaronut♦Jan 28 '13 at 12:57

Too much water for such a small amount of pasta! You should only need 1 l per 300 g of uncooked dried pasta
–
TFDJan 21 '13 at 1:28

1

@TFD: the amount that is generally suggested (e.g. by McGee's On Food and Cooking, pasta.it or by any Italian mamma for that matters) is 1l per 100g, with 10g salt, pretty standard. You would add more for large pasta, such as lasagne, unless you want them to stick.
–
nicoJan 21 '13 at 8:03

@TFD: try to cook fresh egg pasta with water just covering it and then you'll tell me. Of course you can stay there constantly stirring, but I generally like doing other things in the meantime.
–
nicoJan 21 '13 at 9:41

1

Sometimes it's not a bad idea to use more salt then necessary as there are sauces that are made without adding salt, so your pasta can take a bit more salt. Most of the time it's safe to use that 100 + 1 + 10 rule though.
–
SvenJan 22 '13 at 0:22

Salt doesn't lower the boiling point of water, it elevates it. Even so, the amount of salt you add to pasta water (10g/litre is a good guide) will barely make a difference. You need to add nearly 6 times that amount of salt to a litre of water to raise its boiling point by 0.5°C.

As throwing things into boiling water can result in splashing, I suggest adding it to the water before you bring it to a boil.

I'm going to argue for adding the salt after a boil, but before adding the pasta ... because I have stainless steel pots.

If you add salt to cold water, it won't disolve and disperse quickly. This results in the salt falling to the bottom of the pot, then slowly disolving there but not mixing. This increased concentration of salt can end up causing pitting.

Instead, I bring the water to a boil, toss in the salt, then bring it back to a boil (mostly because the lid was off, not because I significantly moved the boiling point), add the pasta, stir it 'til it's all fitting in the water and not clumping together, put the lid back on, bring back to a boil, then reduce the heat (as we only need to maintain a boil we need less energy than trying to elevate the temperature; the less rapid boiling also reduces the odds of the starchy foam boiling all over the place).

I won't say the pitting could not happen, but typically the pot will come to a boil within ten minutes or so--certainly less than an hour for any reasonable pot size and burner power level. This doesn't leave much time for such a reaction. I have been putting the salt in along with the water with my stainless pots (Admittedly, they are All-Clad which are high quality, if overpriced) for years with no ill effects.
–
SAJ14SAJJan 20 '13 at 13:15

The time it takes to boil depends on the amount of water and the size of your burner ... I've cooked in some kitchens where you were lucky to get a pot boiling in 15-20 min. And even with 10 min, if you're cooking pasta night after night like we did growing up (Italian American family), over time it adds up.
–
JoeJan 20 '13 at 22:45

KISS ( Keep It Simple Stupid, words I live by. ), add the salt to the pasta(almost all pastas will benefit from salt) water anytime after the water is added to the pot and before the pasta is added. Just please...add the salt.

If you are concerned about corroding your stainless steal pans...(shrugging) find something else to worry about.

There is a reason that stainless is also called CRES(corrosion resistant) steel. You can cause stainless to actually corrode but it's not easy, your more likely to cause discoloration that can be cleaned with a product like Barkeepers Friend.

Some people believe that you should not add the salt to the pot until the water is boiling because, allegedly:

It can cause damage to your pot, inducing pitting in stainless steel. We could not find strong confirming evidence of this (see this question), especially at culinary concentrations and temperatures.

It can raise the temperature that the water must reach to boil. This is true, but trivially so: the temperature difference is on the order of 0.3 degree F. It makes no practical difference in cooking.

The real limit is that you want it dissolved and distributed throughout the water when you add the pasta to begin cooking. I suspect an actual study would show that with strong boiling and the convection it creates, adding the salt with the pasta would probably be equally effective in the sense that it would be distributed very rapidly, but I am not aware of any research here, and it is just as easy to add it earlier.

Since there is no strong credible reason to delay adding the salt, I add it along with the water personally, since it is easier not to forget.

Note: I wrote this answer for a new question, before I saw the duplicate.